I would start by making careful hand sections for light microscopy. It takes practice, but I would start by trimming down a chunk and placing it on a slide, with water to keep it from drying out. Then you can place another slide across it as a guide (like a carpenter's fence). Then, by moving the guide slightly make a second cut. With practice you can get very good sections. Especially with homogeneous tissues like fruits. This will allow you to make rough cell counts and size determination in the light microscope. Use phase-contrast optics if possible

For very thin hand sections make your first cut with the blade edge vertical; and then, not moving the fence, make a second cut with the blade edge angled in slightly. With practice you can produce a nice section in which the thickness varies across the width of the section from very thin at what was the top of the specimen to somewhat thicker at the bottom - wedge-shaped. Once you get the technique down it is quite easy to control the thickness nicely. It's true that the thickness is not uniform across the section, but for most microscopical observation at 20X or higher, the field of view is small enough so that you don't really notice the thickness difference. Use a fresh blade every time! You need to trim the specimen carefully so that it lies flat on the cutting surface (the first slide) and make sure your axial orientation is precise so that you get true cross-sections. Your best and most versatile stain will be Toluidine blue O in water. After you have got a good look at your specimens with that method then you can move on to paraffin embedded or plastic embedded sections. I don't think you should need electron microscopy for this.

I would start by making careful hand sections for light microscopy. It takes practice, but I would start by trimming down a chunk and placing it on a slide, with water to keep it from drying out. Then you can place another slide across it as a guide (like a carpenter's fence). Then, by moving the guide slightly make a second cut. With practice you can get very good sections. Especially with homogeneous tissues like fruits. This will allow you to make rough cell counts and size determination in the light microscope. Use phase-contrast optics if possible

For very thin hand sections make your first cut with the blade edge vertical; and then, not moving the fence, make a second cut with the blade edge angled in slightly. With practice you can produce a nice section in which the thickness varies across the width of the section from very thin at what was the top of the specimen to somewhat thicker at the bottom - wedge-shaped. Once you get the technique down it is quite easy to control the thickness nicely. It's true that the thickness is not uniform across the section, but for most microscopical observation at 20X or higher, the field of view is small enough so that you don't really notice the thickness difference. Use a fresh blade every time! You need to trim the specimen carefully so that it lies flat on the cutting surface (the first slide) and make sure your axial orientation is precise so that you get true cross-sections. Your best and most versatile stain will be Toluidine blue O in water. After you have got a good look at your specimens with that method then you can move on to paraffin embedded or plastic embedded sections. I don't think you should need electron microscopy for this.

If you are interested in fruit cell size primarily and not cell contents, which are mostly vacuole in ripe fruit, try the fixation and light microscopy methods in Redgwell, R.J.. (1997). In vivo and in vitro swelling of cell walls during fruit ripening. Planta, 203(2) pp. 162-173. The microscopists in this group have extensive experience in fruit tissues, both light microscopy and EM.

Be sure to choose a statistically valid sectioning approach and grid counting method for 3D cell size estimation from 2D sections. See e.g. Howard, C., & Reed, M. (2005). Unbiased stereology (2nd ed.). Oxon, United Kingdom: BIOS Scientific Publishers.

I would recommend light microscopy and particularly fluorescent microscope

I made this video for freehand sectioning. Depending on your fruit it might help you https://www.youtube.com/watch?v=71atzEWKYio

May be you can fix your material in glutaraldehide 2%/paraformaldehide 2,5%. This fixative works for both electron and light microscopy. Then, try embedding in paraffin for light microscopy and staining with toludine blue, and in an epoxy resin for EM.

I agree with C F Nome and would add that certain resin embedding techniques are also suitable for light microscopy sections.